Area Forecast Discussion
Issued by NWS Blacksburg, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRNK 220515 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 115 AM EDT Thu Mar 22 2018 .SYNOPSIS... Low pressure will lift northeast to the New England coast Thursday. High pressure briefly returns to the region on Friday followed by another potential winter weather system over the weekend. && .NEAR TERM /THROUGH TODAY/... As of 1130 PM EDT Wednesday... Forecast updated to cancel winter storm warning in the mountains, as snow showers are abating and main support from upper levels has exited along with limited trajectory for upslope. Still should see a few snow showers/flurries early overnight especially in the NC mountains, but no more than an inch or less expected. For those areas that were in the winter storm warning, they have now been placed in a wind advisory for stronger winds gusting 35 to 50 mph. Namely, higher ridges and more concerned with any lingering snow on limbs/trees plus wet ground from the snow causing trees to fall. No other major adjustments were made to the forecast, and have a special weather statement out for black ice due to refreeze further east. Previous discussion from early evening... Adjustments made to PoPs to account for a snow squall currently moving through the New River Valley. While currently not producing any accumulating snow, rates are high enough to suggest that minor accumulations are possible, but not likely. Once this squall dissipates, should be on track that only significant PoPs will be in upslope areas. Also, adjusted overnight winds up slightly per short range HRRR and LAMP guidance. Adjusted current temps to obs but little to no low change required to overnight lows. As of 330 PM EDT Wednesday... 995 mb surface low centered well off the Delmarva coast trails an inverted surface trough westward from its center across central VA into the Alleghany Front. Most significant accumulating snow per radar trends and spotter reports has been mostly in southeast West Virginia. We`re steadily losing the influence of the synoptic-scale significant accumulating snowfall, and in some locations has already since ended. Current temperatures in the upper 20s to mid 30s across the Blacksburg forecast area. Wintry weather and wind will continue to be the focal point in terms of sensible weather. Have made several changes to headlines. The first was to remove the winter weather advisory areas and to clear out a large portion of the Winter Storm Warning. The winter storm warning remains in effect for western Greenbrier, Summers, Mercer, Tazewell, Smyth, Grayson into Alleghany, Ashe and Watauga Counties where the potential exists for significant upslope snow accumulations along with blowing snow. I`ve also issued a impact- based Wind Advisory from the New River Valley to the Blue Ridge, northeast into the southern Shenandoah Valley, Alleghany Mountains and eastern Greenbrier Counties. Though expected winds will likely be either marginal Advisory or sub-Advisory, significant amounts of snow have fallen across this area, and with an expectation of winds increasing tonight into Thursday, the potential for downed trees and powerlines in these areas is elevated. The Wind Advisory runs through noon Thursday. As mentioned, we are quickly losing influence of the primary winter storm. As such, significant snow accumulations in many areas may only linger until early evening at the latest and/or have largely ended. I`ve kept the winter storm warnings going for the upslope areas, as snowfall coverage and renewed intensity to light to at times moderate levels should result. Admittedly, portions of the winter storm warning have largely underwhelmed in terms of accumulations to this point, especially in Watauga and Ashe Counties in NC and into the Mountain Empire region. Did think about downgrading to Advisories for these areas, but after collaboration with surrounding offices, decided to opt for consistency and will maintain the warnings. Upslope snow should really occur this evening through about midnight, and snow will tend to taper from south to north thereafter. Still looking at an additional 2 to 4 inches, with as much as 5 inches along higher ridges in the winter storm warning area. Have also included mention of black ice in the HWO as temperatures cool into the 20s tonight. Specific to the winds, northwest winds will begin to increase tonight. Admittedly, northwest wind gusts peaking between midnight and mid-morning Thursday probably will be quite marginal. However, much of the Wind Advisory area has accumulated significant amounts of snow (between 4 and 10 inches, see public information statement). We had already heard of trees being downed in parts of Summers County due to the weight of snow in the Talcott area. That potential will be greater in the Wind Advisory area with snow-weighted trees and power lines. Threat may also exist in the winter storm warning area, but for now have mentioned potential for downed trees and power lines in the winter storm warning text statement. Peak northwest wind gusts should be between 35 and 50 mph. Clearing conditions expected on Thursday as high pressure builds back into the region. Northwest wind gusts will still be rather strong in the morning hours, but 850 mb wind max begins to decrease and pressure rises begin to drop as the coastal low continues to move away. Mostly sunny skies should also allow for some snowmelt to occur. Highs mid/upper 30s to the low 40s west of the Blue Ridge, into the 40s and near 50 across the Piedmont and Southside. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... As of 330 PM EDT Wednesday... High pressure in the Ohio Valley will build east across our region Thursday night. The upper trof along the East Coast will slide east into the Atlantic ocean. Low temperatures Thursday night will range from the upper teens in the mountains with snow pack to the lower 30s in the piedmont. Temperatures will moderate on Friday with the warm advection just in advance of the next upstream system that may bring back high clouds during the day. High temperatures on Friday will vary from around 30 degrees in the northwest mountains in Greenbrier county to the mid 50s in the Piedmont. Clouds will continue to increase and lower from northwest to southeast Friday night. Low pressure and its associated war front will lift north Friday into Friday night. Some spotty light rain or snow could also work in far western sections late. Low temperatures will generally be from the upper teens in the mountains to the lower 30s along the southern Blue ridge. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 330 PM EDT Wednesday... Low pressure tracks from Tennessee Saturday afternoon, across the Tennessee Valley and Carolinas to the western Atlantic by Sunday afternoon. All the energy will transfer to the coastal low by Sunday night which move northeast in the Atlantic ocean on Monday. Some differences in the guidance how far south this low will move, which in turn will impact where the winter weather will be on the northern side of the baroclinic zone. Timing has been fairly consistent, keeping the best probability of precipitation from Saturday afternoon into Sunday morning. The GFS is faster than ECMWF with spreading of the moisture east. The axis of the heaviest QPF is Variable depending on Model choice. Will mention winter storm potential in HWO. While too early to pin point exact details, looks like the heaviest snow potential will occur in the northwest mountains especially western Greenbrier. Surface high pressure wedges down the east slopes of the Appalachians Monday and Tuesday. Will hold on to isolated pops in case precipitation over the Tennessee and Ohio Valley spills east into the mountains. Another cold front approaches from the west Wednesday and drop south through our region Wednesday night into Thursday. Temperatures will remain below normal through the period, especially daytime highs. && .AVIATION /05Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 115 AM EDT Thursday... Snow showers/flurries should continue to fade overnight as drier air works in from the north behind the departing upper low along the coast. However KBLF and KLWB will continue to see MVFR to IFR ceilings under northwest flow, with VFR ceilings lingering east of the mountains until Thursday morning. Should finally see ceilings rise to VFR Thursday morning over the west as well allowing for widespread VFR across all sites this afternoon. Gusty northwest winds are expected during the TAF period as the pressure gradient between the approaching upstream high and the strengthening Noreaster becomes stronger overnight into early Thursday. Wind gusts to 35-40 kts could occur mainly along the ridges and including KROA into Thursday. Extended Aviation Discussion... Mainly VFR conditions are expected by Thursday night through Friday night under weak high pressure. Saturday into Sunday, a return to sub-VFR conditions is expected as our next potential winter weather system crosses the area. VFR to return on Monday with high pressure to the north wedged south along the mountains.
-- End Changed Discussion --
&& .EQUIPMENT... As of 1021 AM EDT Wednesday... The Mount Jefferson NWR remains off the air. The radio unit needed to repair the system is expected to arrive tomorrow (Thursday). The earliest this system will again be operational will be Thursday afternoon. && .RNK WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
VA...Wind Advisory until noon EDT today for VAZ007-009>020-022>024- 035. NC...Wind Advisory until noon EDT today for NCZ001-002-018. WV...Wind Advisory until noon EDT today for WVZ042>044-507-508.
-- End Changed Discussion --
&& $$ SYNOPSIS...JH/WP NEAR TERM...AL/JR/WP SHORT TERM...KK LONG TERM...KK AVIATION...AL/JH/JR EQUIPMENT...AL/AMS is the U.S. government's official web portal to all federal, state and local government web resources and services.